Field of the Invention
This invention relates generally to a fast and robust stop line detector in a vehicle and, more particularly, to a system and method for generating a composite image that includes an original bird's eye view image and a rotated bird's eye view image and using the composite image to simultaneously extract stop lines and lane markers using a fast line filtering algorithm.
Discussion of the Related Art
Modern vehicles are becoming more autonomous, that is, modern vehicles are able to provide driving control with less driver intervention. Cruise control systems have been on vehicles for a number of years where the vehicle operator can set a particular speed of the vehicle, and the vehicle will maintain that speed without the driver operating the throttle. Adaptive cruise control systems have been recently developed in the art where not only does the system maintain the set speed, but will also automatically slow the vehicle down in the event that a slower moving vehicle is detected in front of the subject vehicle by using various sensors such as radar and cameras. Modern vehicle control systems may also include autonomous parking where the vehicle will automatically provide the steering control for parking the vehicle, and where the vehicle will stop or alert a driver to stop if a stop line in a roadway is detected.
Stop line detection and lane marker detection in autonomous and partially autonomous vehicles is known in the art. A stop line is a solid white line on a roadway that indicates a location where a vehicle traveling along the roadway is expected to stop. In the United States, these solid white stop lines have a width of approximately 12 to 24 inches. In Japan the width is approximately 0.3 to 0.45 meters, and in China the width of the stop line is approximately 0.2 to 0.4 meters. In all countries the stop lines are perpendicular to lane marker lines. When using known stop detection systems, these systems may be unreliable because dirt, tire polish and unclear stop line markers may pose a problem. For example, known edge detectors such as Sobel and Canny edge detection may be inaccurate when detecting a line candidate against dirt, illumination variation and other noise, thereby posing a safety risk. Additionally, known algorithms are complicated, with or without associated lane markers. Thus, there is a need in the art for a fast and robust stop line detection system that reduces processing time and increases vehicle safety.